1. Field of the Invention
Exemplary aspects of the present invention generally relate to a liquid ejection head and an image forming apparatus including the liquid ejection head.
2. Description of the Related Art
One type of image forming apparatus such as a printer, copier, plotter, facsimile machine, or multifunction device having two or more of these capabilities is an inkjet recording device employing a liquid ejection recording method. The inkjet recording device includes a recording head constructed of a liquid ejection head that ejects droplets of a recording liquid such as ink onto a sheet of a recording medium to form an image on the sheet.
The liquid ejection head is generally constructed of a nozzle plate in which multiple nozzles that eject liquid droplets are formed, a channel plate in which grooves that form part of multiple pressure chambers respectively communicating with the multiple nozzles are formed with partition walls interposed between the grooves, and a wall member such as a vibration plate that covers the grooves to form part of walls of the pressure chambers and a substrate provided with a heat element. The channel plate has through-holes that connect the pressure chambers and the nozzles, respectively.
Increasing demand for higher quality images at higher speed increases the number and density of the nozzles formed in the liquid ejection head, and therefore, each of the partition walls provided between channels, each constructed of the through-hole, the pressure chamber, and so forth, tends to be thin.
The thin partition walls between the channels cause adjacent channel crosstalk, in which pressure applied to a target pressure chamber to eject liquid droplets adversely affects other pressure chambers adjacent to the target pressure chamber and causes pressure fluctuation also in the adjacent pressure chambers. Consequently, liquid droplets are not properly ejected from the nozzles, or liquid droplets are ejected from nozzles provided corresponding to the pressure chambers which are not supposed to eject liquid droplets, thereby degrading image quality.
In order to prevent deformation of the partition walls respectively provided between the adjacent through-holes, there is known a technique in which one of the two adjacent through-holes is shaped like a crank and the through-holes are provided in a zigzag pattern in a direction of nozzle arrays each constructed of the multiple nozzles. In another approach, two types of through-holes, that is, first and second through-holes, are provided and one of the first and second through-holes is provided at a slant.
However, both approaches have drawbacks.
In the case in which one of the two adjacent through-holes is shaped like a crank, channels respectively constructed of the two adjacent pressure chambers have a different shape from the pressure chambers to the nozzles, thereby varying liquid ejection performance between the adjacent pressure chambers.
In the case in which one of the first and second through-holes is provided at a slant, provision of the two types of the through-holes for the single pressure chamber complicates the configuration. In addition, because the volume of each of the pressure chambers needs to be increased, speed of pressure response is decreased. As a result, it is difficult to drive the liquid ejection head with high frequency.